Carbon nanotubes have been the subject of intense studies for over a decade now. Carbon nanotubes can be single-walled or multi-walled. Single-walled carbon nanotubes (SWNTs) can be viewed as sheets of graphene rolled into cylinders with diameters of about 1-10 nm and lengths of about 100-500 nm (Dai, H., Acc. Chem. Res., 35:1035-1044 (2002)). Gases such as NH3, H2, NO2, SO2, CO2, F2, CF4, and O3 have already been studied for functionalization and/or encapsulation into the SWNTs (Ellison, M. D. et al., J. Phys. Chem. B, 108:7938-7943 (2004); Pekker, S. et al., J. Phys. Chem. B, 105:7938-7943 (2001); Feng, X. et al., J. Am. Che. Soc., 127:10533-10538 (2005); Zhao, X. B. et al., J. Phys. Chem. B, 109:8880-8888 (2005); Yim, W. L. et al., J. Phys. Chem. B, 107:9363-9369 (2003); Long, R. Q. et al., Ind. Eng. Chem. Res., 40:4288-4291 (2001); Mercuri, F. et al., J. Phys. Chem. B, 109:13175-13179 (2005); Mickelson, E. T. et al., Chem. Phys. Lett., 296:188-194 (1998); Byl, O. et al., J. Am. Chem. Soc., 125:5889-5896 (2003); Cai, L. et al., Chem. Mater., 14:4235-4241 (2002); Banerjee, S. et al., J. Phys. Chem. B, 106:12144-12151 (2002)). Most of these studies are conducted at low temperatures due to the weakness of the interactions between the SWNTs and the gases. However, it has been reported that NH3 and NO2 react with SWNTs at room temperature entering into the grooves and interacting with multiple nanotubes, the products of which display significant change in conductivity (Ellison, M. D. et al., J. Phys. Chem. B, 108:7938-7943 (2004)).
One study describes the reaction of HN3 with diamond and hydrogenated diamond surfaces at low temperatures (Thorns, B. et al., Surface Science, 337:L807-L811 (1995)). Accordingly, HN3 may be a suitable reagent for incorporation of the energetic azide moiety into host carbon based molecules.
The present invention relates to the interaction of SWNTs with hydrazoic acid (HN3) as a method to form SWNTs with energetic groups incorporated therein.